The amino acid sequence of stellacyanin from the lacquer tree

Bergman, Claes; Gandvik, Eva-Karin; Nyman, Per Olof; Strid, Lars

doi:10.1016/s0006-291x(77)80084-3

Cited by 122 publications

(61 citation statements)

References 23 publications

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“…(ii) The assignment of the =260-cm'1 peak appearing in all blue copper proteins as the Cu(II)-S(Met) stretching mode is in agreement with the observation of peaks near 270 cm-1 in the Raman spectra of copper-polythiaether complexes (20) but does not account for the absence of methionine in stellacyanin (21). The 267-cm' peak in stellacyanin has been rationalized as a possible Cu(II)-disulfide vibration (20).…”

supporting

confidence: 82%

Normal coordinate analysis of the copper center of azurin and the assignment of its resonance Raman spectrum.

Thamann¹,

Frank²,

Willis³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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Normal coordinate analysis that utilizes a general valence force field and the Wilson FG matrix method has been applied to several structural models representing the active site of the blue copper protein, azurin. The models included tetrahedral and square planar CuN2SS', trigonal CuN2S, and trigonal bipyramidal CuN2SS'O structures in which the Ns are imidazole nitrogens of histidines, S is the thiolate sulfur ofcysteine, S' is the thioether sulfur ofmethionine, and 0 is a peptide carbonyl oxygen. For constant Cu-ligand bond lengths and initial force constants, the force field was refined against the most intense ofthe observed frequencies (424, 404, 369, and 261 cm-) in the resonance Raman spectrum of Pseudomonas aeruginosa azurin. The most satisfactory fit between observed and calculated frequencies occurs for tetrahedral and trigonal structures. The calculations provide detailed assignments for the resonance Raman spectrum of azurin and reveal considerable mixing of Cu-S(Cys) and Cu-N(His) vibrational modes. The trigonal model is favored because it is shown that the =260-cm-vibration is an invariant feature in the resonance Raman spectra ofblue copper proteins, even those lacking a methionine in the vicinity of the copper atom. The present analysis ascribes the high frequencies ofthe Cu-ligand stretching modes and the resonance enhancement to the coupled nature of their vibrations and the Franck-Condon overlaps with predominant (Cys)S--Cu(II) charge transfer bands in the visible region.

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supporting

confidence: 82%

Normal coordinate analysis of the copper center of azurin and the assignment of its resonance Raman spectrum.

Thamann¹,

Frank²,

Willis³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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“…1 and table 1) and narrow EPR hyperfine splitting ( fig.2 and table 2) associated with a type 1 Cu(II) site. This shows that a methionine sulfur is not necessary to create a blue copper site, as also evidenced by the fact that stellacyanin does not contain a methionine residue [8]. The ratio of the absorbance around 630 nm to that at 280 nm is lower in the mutant compared to the wild-type protein (table 1), indicating that Cu(II) is not occupying the blue site in all molecules of the mutant protein, because some is lost in the purification due to the lower stability of the mutant protein (see section 3).…”

Section: Discussionmentioning

confidence: 86%

Rack‐induced bonding in blue copper proteins: Spectroscopic properties and reduction potential of the azurin mutant Met‐121 → Leu

et al. 1989

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Site-directed mutagenesis has been used to prepare azurin in which the methionine-121 residue has been replaced by leucine. The oxidized mutant protein displays the strong blue color and characteristic EPR signal of a type 1 Cu(II) ion, showing that methionine is not an obligatory component of a blue copper :site. The optical absorption maximum is shifted 5 nm towards longer wavelength and the extinction coefficient increased by about 10% compared to the wild-type protein.In addition, there are small changes in the EPR parameters, in particular the copper hyperfine splitting. The reduction potential is increased by 70 mV. The results show that a small change in primary structure without any alteration in the three strong ligands can perturb the Cu(II) site and shift the reduction potential, in accord with the concept of rackinduced bonding in blue copper proteins.

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“…There are also homologous cysteine, histidine, and methionine residues in human and bovine cytochrome oxidase. Stellacyanin (21) and fungal laccase B (22) are also homologous to ceruloplasmin in this region; indeed, the 19-kDal fragment of ceruloplasmin and laccase have the identical sequence Leu-His-Cys-His. We propose, therefore, that the binding site for type 1 copper is similar in the small blue electron-transfer proteins and n the large multicopper oxidases and that all these enzymes may have evolved from the same ancestral gene that coded for a small blue protein having electron-transfer or oxidase function.…”

Section: Resultsmentioning

confidence: 99%

Internal duplication and evolution of human ceruloplasmin.

Dwulet¹,

Putnam²

1981

Proc. Natl. Acad. Sci. U.S.A.

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With ihe completion of the primary structure of the 50,000-and 19,000-dalton fragments of human ceruloplasmin [ferroxidase; iron(il):oxygen oxidoreductase, EC 1.16.3.11], over halfofthe covalent structure ofthe single polypeptide chain ofthis protein is known. Visual and computer analysis of the sequence of the 564 amino acid residues in the two fragments gives clear evidence of statistically significant internal homology suggestive of evolutionary replication of two smaller units. Two homology regions, each composed of 224 residues, were defined by an intrasequence alignment that required only three gaps in each 224-residue segment. The two homology regions exhibited 43% identity in sequence, and 13% of the remaining positions had similar residues. The sequence ofa 160-residue segment in ceruloplasmin exhibits significant homology to the active (copper-binding) sites of blue electron-transfer proteins such as azurins and plastocyanins and multicopper oxidases such as cytochrome oxidase and superoxide dismutase. It is proposed that a primitive ceruloplasmin gene was formed by the fusion of two genes coding, respectively, for proteins about 160 and 190 amino acid residues in length and that this precursor gene coding for about 350 amino acids was later triplicated to form the gene for the present-day ceruloplasmin molecule of about 1050 amino acids.Analytical and statistical comparison of amino acid sequences has been a powerful method for detection and estimation of structural similarities among and within proteins, for evaluation of structure-function relationships in a family of proteins, and for study of genetic change in the course of evolutionary development of a class of proteins (1-3). The comparison may be done by visual alignment oftwo sequences for best fit as judged both by identity and similarity of paired amino acids at corresponding positions; gaps in the sequences are sometimes inserted to maximize the fit. Statistical methods for assessing relatedness of proteins are based on computer programs that accumulate pair scores for two amino acids, using a mutation data matrix based on physical and structural parametersg and codon differences for all possible pairs ofamino acids (4) or from actual accepted point mutations accumulated from related sequences (5). By such means the degree of intersequence or intrasequence homology may be assessed; here "homologous" is used to mean matching (identical or similar) in structure, position, physical characteristics, and codons.With the recent completion of the primary structures of the 50,000-dalton (50-kDal) (6) and 19,000-dalton (19-kDal) (7-9) fragments ofhuman ceruloplasmin [ferroxidase; iron(II):oxygen oxidoreductase, EC 1.16.3.1], 564 residues of the amino acid sequence of the single polypeptide chain of this protein are known. These fragments are from the carboxyl terminus of the molecule and account for more than halfofthe primary structure of this blue copper oxidase. During our study we identified a remarkable degree of internal homology in c...

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The amino acid sequence of stellacyanin from the lacquer tree

Cited by 122 publications

References 23 publications

Normal coordinate analysis of the copper center of azurin and the assignment of its resonance Raman spectrum.

Normal coordinate analysis of the copper center of azurin and the assignment of its resonance Raman spectrum.

Rack‐induced bonding in blue copper proteins: Spectroscopic properties and reduction potential of the azurin mutant Met‐121 → Leu

Internal duplication and evolution of human ceruloplasmin.

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